The principal objectives of the training grant are to educate promising pre- and postdoctoral students to be biostatistical scientists in cancer. Ten predoctoral and two postdoctoral trainees are requested. The term biostatistical science refers to the use of the methods of statistics, probability, computer science and mathematics to increase our knowledge and understanding of biomedical phenomena. The course of study for predoctoral students includes probability, statistics, and computing. All students are required to take a concentration in courses related to cancer. There is a close relationship with Dana-Farber Cancer Institute where many of the students are in residence. During the first and second summer periods in the program, predoctoral students are involved in a special program which allows them to participate in the research activities of the Dana-Farber Cancer Institute. After the first summer, many of the students take up residence at the Dana-Farber Cancer Institute and continue their projects. One of the goals for the program is to enable the predoctoral students to carry out dissertation research on new statistical methodology. Nearly all of the dissertation research is on methods related to cancer research. The postdoctoral students may be those who have completed a doctorate in statistics or biostatistics who are carrying out postdoctoral research on cancer related activities or doctoral recipients from another field who generally attend courses the first year and start their postdoctoral research the second year. The postdoctoral students are closely involved with the practice of biostatistics in cancer and are in residence at the Dana-Farber Cancer Institute. An important part of the training is a working seminar on quantitative issues in cancer research. The seminar serves as a forum to discuss current issues in cancer research.